There is no comprehensive standardized, normed assessment of neurobehavioral performance of normal Or high risk infants during the perinatal period. The specific aim of this project is to develop standardized norms for newborn neurobehavioral performance for gestational age (GA) groups and where appropriate, gender and/or race/ethnicity groups during the perinatal period using a uniquely comprehensive psychometrically sound scale, the Neonatal Intensive Care Research Network Neurobehavioral Scale (NNNS). Standardization of the NNNS will be a significant methodological advance for research in neonatology, pediatrics, pediatric neurology, and child development. It will provide norms to evaluate relations between neurobehavioral status and medical and social status variables, and to evaluate the effects of medical and developmental interventions (including changes in NICU ecology and early intervention) on neurobehavioral status during the perinatal period and at older ages. Furthermore, a standardized instrument will facilitate comparison of studies and the development of large data bases. Standardized norms will have a significant impact on clinical care because norms will identify neonates who are functionally abnormal or suspect and permit the evaluation of individual infants in comparison to the norms. We propose to carry out a prospective longitudinal study on a sample of 720 infants stratified by (1) GA: 1] 28-33 weeks; 2] 34-37 weeks; 3] 38-42 weeks; (2) 3 racial/ethnic groups (Black, Hispanic, White); and (3) gender. Within the boundaries of our exclusion criteria, the medical and social status of the infants will be free to vary. Infants in each GA group will be examined with the NNNS three times: 1] when medically stable +3 days or at Birth + 1 day, 2] Term (i.e., for the term group this is the same as Birth +1 day), and 3] at 44 weeks GA. Gestational age will be carefully defined using the converging measures.